Prior known systems for remote control of lighting fixtures are described in detail in the above-noted copending application Ser. No. 08/407,696.
Thus, the lighting of spaces by a plurality of spaced gas discharge lamps (for example, fluorescent lamps), or incandescent lamps is well known. Commonly, one or more fluorescent lamps are mounted in a fixture with a ballast, and such fixtures are spaced over a ceiling on four foot or eight foot centers. Similarly, overhead fixtures for incandescent lamps may be mounted on centers greater than about two feet. Such lamp fixtures are commonly connected to a single power source and are simultaneously turned on and off or, if provided with dimming capability, are simultaneously dimmed.
It is also known that such overhead fixtures can be individually controlled or dimmed. For example, in a given office space, one worker may prefer or need more or less light intensity than another worker at a spaced work area. Dimming systems are known for selectively dimming the lamps of different fixtures to suit the needs of individual workers. For example, each fixture can be individually hard wired to its own remotely mounted dimmer. However, the installation of this wiring can be quite costly and the determination of which dimmer controls which fixture may not be immediately obvious to the user of the system.
Alternatively the dimmers could be located within each fixture and controlled by signals sent over low voltage wiring or through signals transmitted over the line voltage wiring through a power line carrier system. Unfortunately, both of these approaches require expensive interfaces within each fixture to translate and/or decode the received signals for control of the dimmer.
In another known system, a dimmer with a dimming adjustment control is provided at each fixture, and that control is manually operated, for example by rotating the control with a rigid pole long enough to reach the fixture. In this way, each fixture can be selectively adjusted. However, the system is inconvenient to use and, once the fixture intensity is set, it is difficult or inconvenient to readjust. Moreover, it is difficult to retrofit an existing installation with a control system of this nature.
A known fluorescent controller system is also sold by Colortran Inc. of Burbank, Calif., termed a "sector fluorescent controllers" in which an infrared receiver is mounted at a location spaced from its respective fluorescent lamp fixture. Thus, the receiver is fixed to a T-bar, on the wall, on a louver or is counter-sunk flush with wall or ceiling. A ballast controller may be mounted in the lighting fixture, in addition to a conventional dimming ballast. Wiring is then run from the external infrared receiver into the interior of the fixture to the ballast controller. A hand-held remote control infrared transmitter illuminates the infrared receiver at one or more fixtures to control their dimming level.
The need to run wiring from the external sensor complicates the installation of such devices. Further, since the sensor is spaced from the fixture, it requires separate installation, and is visible to view. Moreover, the infrared transmitter of the Colortran device has a transmitting angle of 30.degree.. Therefore, several receivers can be illuminated simultaneously, making selection of control of only one fixture difficult unless the user places himself in a precise location within the room under the fixture to be controlled.
A similar system is sold by the Silvertown Hitech Corporation, where the infrared receiver is mounted to the louvers of a fluorescent fixture. In this system, the infrared receiver is specifically adapted to be mounted to a specific fluorescent fixture, and it tends to block light output from the fixture.
A further system is sold by Matsushita wherein a single transmitter can be used for independent control of two or more different receivers. This is achieved by adjusting a switch on the transmitter to correspond to a switch setting which has been previously set at the receiver corresponding to the fixture desired to be controlled. For example, fixture A could be controlled when the switch is in position 1 and fixture B could be controlled when the switch is in position 2. In this system, the user must remember which fixture corresponds to which switch position, i.e., A corresponds to 1 and B corresponds to 2.
It is easy for the user to forget and become confused, particularly when there are three or four fixtures controlled by three or four switch positions. This is an undesirable situation. Further, there is a practical limitation on the number of switch positions which can be provided and the number of fixtures in a large room will exceed this. Additionally, there is a great deal of work in programming and reprogramming the receivers for a large number, for example, 20 fixtures.
In comparison with the system of the invention of copending application Ser. No. 08/407,696, as will be described in more detail later, the transmitter is simply pointed at the receiver in the fixture which it is desired to control. This is simple, unambiguous and transparently ergonomic. Further, it does not require any preprogramming or reprogramming of the receivers.
It is also known to use an infrared transmitter for the control of a wall box mounted dimmer, such as the "Grafik Eye" Preset Dimming Control sold by Lutron Electronics Co., Inc., the assignee of the present invention. Also see U.S. Pat. No. 5,191,265 which describes such transmitters. The Grafik Eye Dimmer Control system provides for the remote control of fixtures and other lamps by a control circuit located at the wall box which controls those fixtures and lamps. An infrared transmitter aimed at the wall box housing produces a beam which contains information to turn on and off and to set the light dimming level of the fixtures being controlled to one of a plurality of preset levels, or to continuously increase or decrease the light level. Other similar systems are sold by Lutron Electronics Co., Inc. under the trademark RanaX-Wireless Dimming Control System. Such systems are not intended to control individual ceiling fixtures in a room independently of other closely spaced fixtures (those fixtures spaced up to about two feet apart).
The invention of copending application Ser. No. 08/407,696 solved the problems referred to above. Thus, in accordance with that invention, each fixture to be controlled has a radiation receiver and ballast control circuit mounted in the interior of the fixture housing and is wired internally of the fixture housing to a dimming ballast in the case of a fluorescent fixture. In the case of an incandescent fixture, each light to be controlled has a radiation receiver and dimmer, which is connected to the lamp to be controlled. A small opening in the fixture housing allows optical communication with the radiation receiver and is easily illuminated from substantially any location in the room containing the fixtures. A narrow beam radiation transmitter with a beam angle, for example, of about 8.degree. is employed to illuminate the radiation-receiving opening in the fixture without illuminating the fixtures spaced greater than about two feet from the fixture to be controlled. For rooms about thirty feet by thirty feet in area and ten feet high, fixtures two feet apart can be easily discriminated between one another. For larger spaces, the user can reposition himself to discriminate between closely spaced fixtures.
The receiver is a novel structure containing a printed circuit board mounted across a central area of a typical back box. A radiation sensor is mounted on the printed circuit board and faces an open side of the box which is covered by a yoke. The radiation employed is preferably infrared light and the yoke has an infrared transparent portion to allow infrared radiation to reach the radiation sensor. Narrowly focused, high frequency ultrasound could also be employed.
In addition, either a visible or invisible laser beam with information encoded on it in known manner could be used, with the laser beam being spread by optical means such as a divergent lens. In the case of a visible beam, this would produce a beam like a flashlight pointer which would aid in pointing the transmitter at the receiver.
Finally, narrowly focused radio frequency waves could be used. These could be emitted from a parabolic reflector on the transmitter, using a parabolic reflector of approximately 4.3 cm in diameter and a frequency of 60 GHz. The beam spread would be approximately 8.degree.. The opening used for optical signals would, of course, be modified if radio frequency waves are used.
To install the receiver structure of application Ser. No. 08/407,696, a novel mounting structure is provided whereby a plastic hook and loop type fastener surface is fixed to the yoke and a cooperating hook and loop type surface is attached to the interior of the fixture, preferably on the wire way cover within the fixture. All wires can then be interconnected within the fixture wire-way. An opening is formed in the wire-way cover of the fixture and optically communicates with the radiation receiver within the receiver housing. The receiver housing is easily located within the wire-way housing to communicate with the opening in the wire-way cover and is then pressed in place. An optical lens insert can be installed in the yoke to assist in focusing input radiation on the radiation receiver sensing element. This lens insert can be interchangeable and different lens inserts can be designed to have different angles of acceptance of input radiation.
The lens protrudes slightly through an opening in the fixture housing to receive infrared radiation from the transmitter. The transmitter is an infrared transmitter of the type employed in the Lutron Grafik Eye system previously identified for use with wall box dimmer systems. The Grafik Eye transmitter is an infrared transmitter which transmits signals with twelve different code combinations. The transmitter is operable to transmit a beam angle of about 8.degree. and can, therefore, selectively illuminate relatively closely spaced ceiling fixtures. Depending on the control which is activated, a selected fixture can be dimmed to one of a plurality of preset dim conditions, or can be dimmed continuously up or down. Thus, the transmitter can accomplish raise/lower, presets, low/high end trim and the like. Alternatively, a transmitter with a movable slide or rotary actuator could be used to provide continuous dimming control.
This novel structure had a major advantage in retrofitting an existing installation. Thus, it is only necessary to drill a small opening in the wire-way cover, and mount an infrared receiver/ballast controller to the wire-way cover in line with the opening within the wire-way cover. Light dimming ballasts are then mounted within the fixture wire-way and are interconnected with the receiver/ballast controller within the fixture wire-way without need for external wiring. The wire-way cover with receiver/ballast controller attached is then reinstalled in the fixture.
The previously described invention of application Ser. No. 08/407,696 is also disclosed for use with a large variety of existing fixtures and can also be used with external switches and dimming circuits. Photocells, occupancy sensors, time clocks, central relay panels and other inputs can also be used with the novel system. Furthermore, that invention made it possible for a single receiver to operate any desired number of ballasts.
The primary application of the invention of application Ser. No. 08/407,696 is in large open plan office areas illuminated by overhead fluorescent fixtures, particularly where video display units (e.g., personal computers) are used. However, the invention also has applications in areas which are used for audio visual presentations, in hospitals and elder care facilities, in manufacturing areas and in control rooms, the control of security lighting either indoor or outdoor and to reduce lighting levels for energy conservation.
A further application of the prior invention is in wet or damp locations where normal wall controls cannot be used due to the danger of electric shock or in areas with hazardous atmospheres where there is a danger of explosion if a line voltage wall control is operated and causes a spark. In these cases, the receiver can be located in a protected fixture and the lights controlled by the low voltage hand-held remote control transmitter.
The prior invention was described with respect to the control of light levels. However, the output from the receiver could be adapted in known manner to control motor speed and/or position such as the position of the motors in window shade control systems. The output from the receiver could further be adapted to control other types of actuators such as solenoids.
The above-described invention of application Ser. No. 08/407,696 performs very well. However, it has been found that the system was directionally sensitive due to shadowing and unpredictable reflections of the radiation by the light fixture baffle or lens. It was also found that the system was sensitive to sources of infrared radiation other than the infrared signal of the remote transmitter, and further, that the system was slow in responding to a valid infrared signal from the transmitter because the receiver was waiting for a signal while in an "insensitive" state.
A further problem with the system of application Ser. No. 08/407,696 was that an expensive fiber optic cable was required when the end of the IR receiver was removed some distance, for example, up to 24 inches from the IR receiver housing.